The present invention relates generally to a process for producing food products from legumes. More particularly, the present invention relates to a method for processing legumes to produce high-fiber, high-protein, reduced-flatulence snack foods.
Many types of legumes possess a variety of nutritional components, such as protein and fiber, in advantageous concentrations so that it is desirable to incorporate legumes into food products. In spite of these potentially beneficial sources of nutrients, the use of legumes in food products has been limited because many legumes produce flatulence after their digestion. Flatus produced in a person's intestinal tract not only leads to the potential for social embarrassment, but also causes personal discomfort, including abdominal rumblings, cramps, pain, and diarrhea.
As food is digested in humans, flatus is typically generated in the stomach and intestines. For most people, flatus generation rates are typically between 16 and 64 milliliters per hour. Factors that are known to impact flatus generation rates include diet, age, physiological status, and medical status. One particular type of food that is known to enhance flatus generation rates is legumes. Flatus production rates for certain legumes are as follows:
______________________________________ Food ingredient Intake Flatus Food ingredient Intake Flatus ______________________________________ Full fat Soya 146 g 30 ml/h California 450 g 36 ml/h white beans Soybeans 100 g 36 ml/h Lima beans 100 g 42 ml/h Defatted Soya 146 g 71 ml/h Mung beans 100 g 25 ml/h Navy bean 146 g 179 ml/h Dutch brown 250 g 72 ml/h meal bean Whole Bengal 40 g 52 ml/h Dun peas 210 g 21 ml/h gram Bengal gram 40 g 44 ml/h Lentils 200 g 41 ml/h (cotyledon) California 100 g 120-137 Red kidney 100 g 84 ml/h white beans ml/h beans ______________________________________
Attempts have been made to process legumes to reduce the amount of flatus generated during digestion. A primary drawback of these processes is that in addition to removing sugars that cause flatus, the processes also remove other desirable ingredients, such as vitamins, minerals, and soluble carbohydrates, from the legumes. Because these desirable ingredients are removed from legumes, the nutritional value of legumes is reduced.
Rockland et al., U.S. Pat. No. 3,318,708 (hereinafter "Rockland et al. '708"), and Rockland et al., U.S. Pat. No. 3,352,687 (hereinafter "Rockland et al. '687") disclose processes for producing quick-cooking legumes. The processes each describe placing dry beans in a hydrating medium and then subjecting the beans to cycles of vacuum and atmospheric pressure until the beans are hydrated to a desired extent. The hydrating medium used in these processes contains sodium chloride, a chelating agent and an alkaline agent. Rockland et al. '708 discloses drying the hydrated beans to a moisture content of between 9.5 and 10.5 percent. Rockland et al. '687 discloses freezing the hydrated beans until the beans are used.
Rockland, U.S. Pat. No. 3,635,728 (hereinafter "Rockland '728") describes a process for making quick-cooking soybean products in which bitterness and other undesired taste qualities of the soybeans are reduced. The process includes briefly contacting the beans with boiling water and then soaking the beans in an aqueous solution containing sodium chloride, a chelating agent, and an alkaline agent. The treated soybeans are then either dried or frozen.
Rockland et al., U.S. Pat. No. 4,124,727 (hereinafter "Rockland et al. '727"), discloses further processing of the hydrated legumes disclosed in Rockland et al. '708, Rockland et al. '687 or Rockland '728 to prepare a nutritionally balanced protein snack foods from legumes. This process includes mashing the hydrated legumes. A dough is then formed by mixing the mashed legumes with water methionine-containing ingredients, such as cereal grain flours, oil seeds, or oil seed flours. The dough is shaped and then fried in an edible oil.
Matsumoto et al., U.S. Pat. No. 4,748,037, describes using a twin screw extruder to produce snack-like cakes from various types of beans. The process includes feeding whole or hulled beans into a twin-screw extruder. During the extrusion process, the moisture content of the beans is between 8 and 50 percent. Extrusion causes the starch component of the beans to swell while texturizing the protein component of the bean so that the beans are formed into a cake.
Wagner et al., U.S. Pat. No. 3,876,807, describes a process for increasing the digestibility of legumes by maintaining the legumes in a medium having a pH of between 5.0 and 5.5 and a temperature of between 45.degree. C. and 55.degree. C. for between 24 and 48 hours. Lawhon et al., U.S. Pat. No. 4,645,677, discloses a process for removing flatulence-causing sugars from bean products by forming a solution of water and ground beans and then ultrafiltering the solution through a molecular weight cutoff of between 30,000 and 100,000 daltons. Stahel, U.S. Pat. Nos. 4,450,176 and 4,543,264, disclose methods for making beans more digestible by extracting components from the beans by exposing the beans to alcohol vapors.